Detection of hard β-emitting radionuclides in aqueous solutions using Cerenkov radiation: A review article

Abstract

Cerenkov counting of solutions is advocated as a useful means of detecting hard β-emitters; the present work is dedicated to the practical aspects of Cerenkov detection with commercially available liquid scintillation spectrometers. The variations of count rates with the type of vials and the volume of solutions are pointed out. With a spectrometer equipped with S 11 phototubes, detection efficiencies from 16 calibrated sources are found to be 23–50 per cent for emitters of E β maximum in the range 1·3−2·3 MeV and 50–70 per cent up to 3·5 MeV. The results of experiments with various optical filters suggest a direct relationship between the β energy of the isotope and the fraction of Cerenkov light emitted in the ultra-violet region. Pulse height analysis either by calculation of the channel ratio obtained from the spectrometer or by direct oscilloscopic display of spectra enables the energy of any unknown β-emitter to be evaluated. Color quenching of biological solutions inhibits more widespread use of Cerenkov counting while solute quenching is shown not to be a problem. Changes induced by 31 wavelength shifters are assessed; we single out Esculin as one of the most effective. Stress is being put on the advantages of Cerenkov counting of 42K, 32P, 86Rb and 24Na and the applicability of the method to more than 40 β-emitters having maximum beta energies above 1 MeV.